JPH07205469A - Thermal head - Google Patents
Thermal headInfo
- Publication number
- JPH07205469A JPH07205469A JP4071014A JP7101492A JPH07205469A JP H07205469 A JPH07205469 A JP H07205469A JP 4071014 A JP4071014 A JP 4071014A JP 7101492 A JP7101492 A JP 7101492A JP H07205469 A JPH07205469 A JP H07205469A
- Authority
- JP
- Japan
- Prior art keywords
- heating element
- temperature
- current
- circuit
- printing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/35—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads providing current or voltage to the thermal head
- B41J2/355—Control circuits for heating-element selection
- B41J2/36—Print density control
- B41J2/37—Print density control by compensation for variation in current
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/35—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads providing current or voltage to the thermal head
- B41J2/355—Control circuits for heating-element selection
- B41J2/36—Print density control
- B41J2/365—Print density control by compensation for variation in temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/335—Structure of thermal heads
- B41J2/33505—Constructional details
- B41J2/3351—Electrode layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/335—Structure of thermal heads
- B41J2/33505—Constructional details
- B41J2/33515—Heater layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/345—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads characterised by the arrangement of resistors or conductors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
- B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
- B41J2/35—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads providing current or voltage to the thermal head
- B41J2/355—Control circuits for heating-element selection
- B41J2/3553—Heater resistance determination
Landscapes
- Electronic Switches (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明はサーマルヘッドに関
し、特に発熱素子の材料および印字制御回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head, and more particularly to a material of a heating element and a print control circuit.
【０００２】[0002]
【従来の技術】従来のサーマルヘッドでは、印字の開始
直後は印字濃度が薄く、また印字が連続した場合には印
字の時間とともに濃度が高くなるという問題があった。
これは、印字のためにサーマルヘッドの発熱素子に供給
されるエネルギーが、発熱素子近傍の基材やサーマルヘ
ッド自体に畜熱されるために生じるものである。この畜
熱による印字濃度の変化は、印字品質を劣化させること
から、種々の方法により畜熱の対策がなされている。2. Description of the Related Art A conventional thermal head has a problem that the print density is low immediately after the start of printing, and if the print is continuous, the print density increases with the printing time.
This occurs because the energy supplied to the heating element of the thermal head for printing is stored in the base material near the heating element and the thermal head itself. Since the change in the print density due to the heat storage heat deteriorates the print quality, various methods have been taken for the heat storage heat.
【０００３】例えば、印字履歴情報に基づき印加エネル
ギーを補正する方法がある。この方法は、キャラクタ印
字のように印字率が小さく、その印字率の変化も少ない
場合には、比較的短時間の補正により印字品質の劣化が
抑制可能であった。しかし、グラフィック印字のよう
に、サーマルヘッドの発熱素子の並置方向および時間軸
方向に印字率の変化が大きい場合には非常に多くの印字
履歴情報を必要とし、その実現には大規模の集積回路を
要すると云う問題があった。For example, there is a method of correcting applied energy based on print history information. In this method, when the printing rate is small like character printing and the change in the printing rate is small, the deterioration of the printing quality can be suppressed by the correction in a relatively short time. However, as in the case of graphic printing, when there is a large change in the printing rate in the juxtaposition direction of the heating elements of the thermal head and in the time axis direction, a great deal of printing history information is required, and the realization of a large scale integrated circuit There was a problem that it required.
【０００４】また、サーミスタ等の温度センサを発熱素
子の近傍に設け、その温度情報を基にして印字エネルギ
を補正する方法もある。しかしながら、この方法ではセ
ンサを発熱素子自体に接して配置することは不可能であ
り、発熱素子の実温度とセンサで検出した温度との間に
は時間的な遅れが生じる。さらに、センサ自体の熱応答
特性も無視できないことから、印字に要求される時間単
位での補正は不可能であった。There is also a method in which a temperature sensor such as a thermistor is provided in the vicinity of the heating element and the printing energy is corrected based on the temperature information. However, with this method, it is impossible to dispose the sensor in contact with the heating element itself, and there is a time delay between the actual temperature of the heating element and the temperature detected by the sensor. Further, since the thermal response characteristic of the sensor itself cannot be ignored, it was impossible to make correction in the time unit required for printing.
【０００５】一方、近年、カラーの印字の用途が益々増
大する傾向にあり、この場合には印字濃度に微妙な諧調
度も要求され、サーマルヘッドの畜熱補正は更に分解能
を上げる必要が生じている。On the other hand, in recent years, the use of color printing tends to increase more and more, and in this case, a delicate gradation is required for the printing density, and it is necessary to further increase the resolution of the thermal head thermal correction. There is.
【０００６】[0006]
【発明が解決しようとする課題】本発明が解決しようと
する課題、すなわち本発明の目的は、発熱素子の電気抵
抗値の変化によりその温度を検知するようにして上記の
問題点を改善したサーマルヘッドを提供することにあ
る。SUMMARY OF THE INVENTION The problem to be solved by the present invention, that is, the object of the present invention is to detect the temperature of a heating element by the change of the electric resistance value of the heating element, thereby improving the above-mentioned problems. To provide the head.
【０００７】[0007]
【課題を解決するための手段】本発明のサーマルヘッド
は、電気抵抗の温度依存性が大きな材料で形成した発熱
素子と、前記電気抵抗の変化に基づき前記発熱素子の温
度を検出する回路と、検出された前記温度を基に前記発
熱素子への印加エネルギーを制御する回路とを具備す
る。A thermal head of the present invention comprises a heating element formed of a material having a large temperature dependence of electric resistance, a circuit for detecting the temperature of the heating element based on a change in the electric resistance, And a circuit for controlling energy applied to the heating element based on the detected temperature.
【０００８】また、本発明のサーマルヘッドにおいて、
印加エネルギーを制御する回路は、発熱素子の到達温度
を予め設定し、前記発熱素子の温度が前記到達温度に到
達すると同時にエネルギーの供給を中止し、前記発熱素
子の温度を一定に制御するようにして構成される。Also, in the thermal head of the present invention,
The circuit for controlling the applied energy presets the ultimate temperature of the heating element, stops the supply of energy at the same time when the temperature of the heating element reaches the ultimate temperature, and controls the temperature of the heating element to be constant. Consists of
【０００９】ここで、発熱素子を形成する材料が有する
電気抵抗の温度依存性は正・負を問わないが、負に大き
な温度依存性を有する方が発熱素子面内での熱集中が顕
著になり、微妙な諧調度を要求される印字に適してい
る。The temperature dependence of the electric resistance of the material forming the heating element may be positive or negative. However, if the material has a large negative temperature dependence, the heat concentration on the surface of the heating element becomes more remarkable. Therefore, it is suitable for printing that requires a fine gradation.
【００１０】発熱素子の温度を検出する回路は、印字の
ための電圧が発熱素子に印加されたときに流れる電流を
常時モニターし、その電流値を基に計算した発熱素子の
抵抗値と発熱素子が有する抵抗温度係数より求められる
抵抗値との関係から発熱素子の温度を決定する。The circuit for detecting the temperature of the heating element constantly monitors the current flowing when a voltage for printing is applied to the heating element, and calculates the resistance value of the heating element and the heating element calculated based on the current value. The temperature of the heating element is determined from the relationship with the resistance value obtained from the temperature coefficient of resistance of the heating element.
【００１１】上記で決定された温度を基に発熱素子への
印加エネルギーを制御する回路は、その温度が別に規定
された値以上になると発熱素子への印加エネルギーを抑
制し、また規定された値以下になると印加エネルギーを
増大させ、印字の間、発熱素子の温度を常に一定に保持
する機能を有する。The circuit for controlling the applied energy to the heating element based on the temperature determined above suppresses the applied energy to the heating element when the temperature exceeds a value specified separately, and also controls the applied energy to the specified value. In the following cases, the applied energy is increased to keep the temperature of the heating element constant during printing.
【００１２】また、上記発熱素子への印加エネルギーを
制御する回路は、発熱素子が規定された温度に到達する
と同時にエネルギーの供給を中止することにより、当該
発熱素子の温度が規定値以上になることを防止する機能
であってもよい。Further, in the circuit for controlling the energy applied to the heating element, the temperature of the heating element becomes equal to or higher than the specified value by stopping the supply of energy at the same time when the heating element reaches the specified temperature. It may be a function of preventing.
【００１３】[0013]
【実施例】以下、本発明について図面を参照しながら説
明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
【００１４】図１は本発明の一実施例の原理を説明した
ブロック図である。同図において、発熱素子にエネルギ
ーを印加する時間を決めるストローブ信号発生器１０１
は、印字サイクル毎にストローブ信号を発生する。この
ストローブ信号がＨレベルの時間の間はドライブ回路１
０２が駆動され、発熱素子１０４には電圧Ｖが印加され
て電流Ｉが流れる。FIG. 1 is a block diagram illustrating the principle of an embodiment of the present invention. In the figure, a strobe signal generator 101 that determines the time for applying energy to the heating element
Generates a strobe signal every print cycle. While the strobe signal is at H level, the drive circuit 1
02 is driven, a voltage V is applied to the heating element 104, and a current I flows.
【００１５】発熱素子１０４は図２に示すような負の温
度係数をもっており、本実施例では、２５原子％のアル
ミを含んだクロム合金の薄膜を用いた。この発熱素子１
０４の抵抗値について、印字開始時は室温で１．６７ｋ
Ωであるが、印字の開始とともに発熱素子１０４の温度
が上昇し、その抵抗値は図２のカーブに沿って減少す
る。The heating element 104 has a negative temperature coefficient as shown in FIG. 2, and in this embodiment, a chromium alloy thin film containing 25 atomic% of aluminum was used. This heating element 1
Regarding the resistance value of 04, 1.67k at room temperature at the start of printing
Ω, the temperature of the heating element 104 rises with the start of printing, and its resistance value decreases along the curve of FIG.
【００１６】この発熱素子１０４には、電流検出用の抵
抗ｒ（１０３）が直列に挿入されており、これらの抵抗
値は ｒ＜＜Ｒ （１） の関係にある。A resistor r (103) for current detection is inserted in series in the heating element 104, and the resistance values thereof are in the relation of r << R (1).
【００１７】ここで、発熱素子１０４に印加されている
電圧Ｖは固定であり、本実施例の場合には２４Ｖとし
た。そのため、発熱素子１０４に流れる電流Ｉは Ｉ＝２４／Ｒ （２） の式であらわされ、この電流Ｉにより画一的にＲが決定
される。Here, the voltage V applied to the heating element 104 is fixed, and is 24 V in the case of the present embodiment. Therefore, the current I flowing through the heating element 104 is expressed by the formula I = 24 / R (2), and R is uniformly determined by this current I.
【００１８】一方、電流検出器１０５の出力電圧Ｖは Ｖ＝ｒ×Ｉ＝ｒ×２４／Ｒ （３） であり、よって抵抗１０８に流れる電流は（２）で求め
られる値となり、発熱素子の抵抗値に反比例した値とな
る。On the other hand, the output voltage V of the current detector 105 is V = r × I = r × 24 / R (3) Therefore, the current flowing through the resistor 108 becomes the value obtained in (2), and The value is inversely proportional to the resistance value.
【００１９】ここで、発熱素子に電圧が印加された時の
上昇温度Ｔ０を３５０℃に設定した場合、抵抗値Ｒ０は
図２より１．１５ｋΩであり、その時の電流Ｉ０は Ｉ０＝２４／１．１５＝２１ｍＡ と計算されて設定器１０６から比較器１０７に入力され
ている。Here, when the rising temperature T0 when a voltage is applied to the heating element is set to 350 ° C., the resistance value R0 is 1.15 kΩ from FIG. 2, and the current I0 at that time is I0 = 24/1. .15 = 21 mA is calculated and input from the setter 106 to the comparator 107.
【００２０】電流検出器１０５で検出された電流ＩがＩ
０より大きくなる、すなわち発熱素子１０４の温度がＴ
０を越えると、比較器１０７の出力がＬレベルからＨレ
ベルに変化し、ＦＦ１０１をリセットしてストローブ信
号をＬに落とす。そのため、駆動回路１０２の動作が停
止し、発熱素子１０４に電流が流れなくなる。The current I detected by the current detector 105 is I
0, that is, the temperature of the heating element 104 is T
When it exceeds 0, the output of the comparator 107 changes from the L level to the H level, and the FF 101 is reset to drop the strobe signal to the L level. Therefore, the operation of the drive circuit 102 is stopped, and the current does not flow to the heating element 104.
【００２１】図５は、この時のストローブ信号と電流波
形との関係を示したものである。時間ｔ０からｔ１の
間、ストローブ信号Ｓ１はＨレベルであり、発熱素子１
０４には電流が流れ、徐々に抵抗値が減少（すなわち電
流が増大）してＲ０になると、ＦＦ１０１がリセットさ
れてストローブ信号はＬレベルとなり、発熱素子１０４
の電流が遮断されるために発熱素子の温度は低下する。FIG. 5 shows the relationship between the strobe signal and the current waveform at this time. From time t0 to t1, the strobe signal S1 is at the H level, and the heating element 1
When a current flows through 04, and the resistance value gradually decreases (that is, the current increases) to R0, the FF 101 is reset, the strobe signal becomes L level, and the heating element 104.
Since the current is cut off, the temperature of the heating element drops.
【００２２】しかし、発熱素子はガラス基材の表面に配
置されているため、ガラス器材に畜熱が生じており、次
なる印字信号が印加される直前の発熱素子の温度は室温
まで低下していない。この様な減少の累積が印字品質を
劣化させる原因であるが、本発明では、次なる印字周期
のストローブ信号Ｓ２がＨレベルになり発熱素子１０４
の温度が上昇した時、前記したＳ１の場合と同様に、目
的温度Ｔ０に到達すると同時に比較器１０７が働き、Ｆ
Ｆ１０１がリセットされストローブ信号がｔ３のタイミ
ングでＬレベルになる。この様に、印字のためのストロ
ーブ信号の時間幅が発熱素子自体の温度で制御されるこ
とから、発熱素子の温度を常に一定に保つことが可能と
なる。However, since the heating element is arranged on the surface of the glass substrate, heat storage occurs in the glass equipment, and the temperature of the heating element immediately before the next print signal is applied is lowered to room temperature. Absent. The accumulation of such a decrease is a cause of deteriorating the print quality, but in the present invention, the strobe signal S2 of the next print cycle becomes the H level and the heat generating element 104.
When the temperature rises, the comparator 107 is activated at the same time when the target temperature T0 is reached, as in the case of S1 described above.
F101 is reset and the strobe signal becomes L level at the timing of t3. In this way, since the time width of the strobe signal for printing is controlled by the temperature of the heating element itself, it is possible to always keep the temperature of the heating element constant.
【００２３】図３は、発熱素子３２素子のサーマルヘッ
ド全体の回路を示す。シリアル入力Ｓｉｎは、クロック
信号Ｃｌｏｃｋとともに図４に示すタイミングでサーマ
ルヘッドに入力され、シフトレジスタ４０１でシリアル
からパラレルに変換され、ラッチ信号Ｌａｔｃｈのタイ
ミングでラッチ４０２に格納される。同時にＦＦ５３６
から５６７がセットされてＡＮＤゲート４０３から４３
４の片入力がＨレベルになり、ラッチ４０２のデータが
Ｈレベルのものだけ出力がＨレベルとなって、それに対
応するドライブ回路４３５から４６６が動作状態とな
り、発熱素子Ｒ１からＲ３２に電流が流れ発熱する。例
えば、ラッチ４０２の奇数番目のみデータがＨレベルの
とき、奇数番の発熱素子に電流が流れる。FIG. 3 shows a circuit of the entire thermal head having 32 heating elements. The serial input Sin is input to the thermal head together with the clock signal Clock at the timing shown in FIG. 4, converted from serial to parallel by the shift register 401, and stored in the latch 402 at the timing of the latch signal Latch. FF536 at the same time
To 567 are set and AND gates 403 to 43
One of the inputs 4 becomes H level, the output of only the data of the latch 402 is at H level, the output becomes H level, the drive circuits 435 to 466 corresponding thereto become in the operating state, and the current flows through the heating elements R1 to R32. Fever. For example, when only odd-numbered data in the latch 402 is at H level, a current flows through the odd-numbered heating elements.
【００２４】この電流値は、検出用抵抗器４７２から５
０３にかかる電位差によりＡ／Ｄコンバータで検出され
る。予め設定器４７０で設定された電圧値とＡ／Ｄコン
バータ４６９の出力電圧とを比較し、設定電圧を超える
とパルスが出力されてＦＦ５３６から５６７がリセット
されてＡＮＤゲート４０３から４３４が閉じ、発熱素子
Ｒ１からＲ３２に流れる電流が遮断される。This current value is detected by the detecting resistors 472 to 5
The potential difference applied to 03 is detected by the A / D converter. The voltage value set in advance by the setter 470 is compared with the output voltage of the A / D converter 469. When the voltage exceeds the set voltage, a pulse is output, the FFs 536 to 567 are reset, the AND gates 403 to 434 are closed, and heat is generated. The current flowing from the elements R1 to R32 is cut off.
【００２５】なお、本実施例ではＡ／Ｄコンバータ４６
９と比較器４７１とは、図４のＴＳ１からＴＳ３２のタ
イミングパルス群で同期がとられ、時分割による動作を
している。In this embodiment, the A / D converter 46
9 and the comparator 471 are synchronized by the timing pulse group of TS1 to TS32 of FIG. 4, and operate by time division.
【００２６】[0026]
【発明の効果】以上説明したように本発明によれば、次
の効果が得られる。As described above, according to the present invention, the following effects can be obtained.
【００２７】（１）発熱素子自体の温度を基に印字エネ
ルギーを制御し、その温度を一定に保持することが可能
となり、印字濃度の制御精度が著しく向上する。(1) It becomes possible to control the printing energy based on the temperature of the heating element itself and keep the temperature constant, and the control accuracy of the printing density is remarkably improved.
【００２８】（２）発熱素子自体の温度を基に印字エネ
ルギーを制御するので、印字濃度の制御が高速になり、
印字速度が大きい場合にも充分対応できる。(2) Since the printing energy is controlled based on the temperature of the heating element itself, the printing density can be controlled at high speed.
It can be used even when the printing speed is high.
【００２９】（３）発熱素子以外に、特別な温度センサ
を必要としないので、部品の点数および製造工数を低減
できる。(3) Since no special temperature sensor other than the heat generating element is required, the number of parts and the number of manufacturing steps can be reduced.
【００３０】（４）発熱素子に負に大きな温度依存性を
有する抵抗材料を使用することにより、高い諧調度を得
ることが可能となる。(4) By using a resistance material having a large negative temperature dependency for the heating element, it is possible to obtain a high gradation.
【図１】本発明の一実施例の原理を示すブロック図。FIG. 1 is a block diagram showing the principle of an embodiment of the present invention.
【図２】Ｃｒ−Ａｌの抵抗値温度依存特性図。FIG. 2 is a characteristic temperature-dependent characteristic diagram of Cr-Al.
【図３】本発明の実施例の回路図。FIG. 3 is a circuit diagram of an embodiment of the present invention.
【図４】本発明の実施例のタイミング図。FIG. 4 is a timing diagram of an embodiment of the present invention.
【図５】本発明の実施例のストローブ信号と発熱素子の
昇温降下カーブ説明図。FIG. 5 is an explanatory diagram of a strobe signal and a temperature rise / fall curve of a heating element according to the embodiment of the present invention.
１０１ ＦＦ １０２ 駆動回路 １０３ 電流検出用抵抗器（ｒ） １０４ 発熱素子（Ｒ） １０５ 電流検出器 １０６ 目標電流設定器 １０７ 比較器 １０８ 抵抗器 101 FF 102 Drive circuit 103 Current detection resistor (r) 104 Heating element (R) 105 Current detector 106 Target current setting device 107 Comparator 108 Resistor
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成４年１１月２０日[Submission date] November 20, 1992
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１４[Correction target item name] 0014
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１４】図１は本発明の一実施例の原理を説明した
ブロック図である。同図において、発熱素子にエネルギ
ーを印加する時間を決めるストローブ信号発生用のＦＦ
１０１は、印字サイクル毎にストローブ信号１１０を発
生する。ＦＦ１０１へサイクル毎に規則的に入力される
サイクル信号１０９によりＦＦ１０１はセットされ、ス
トローブ信号１１０はＨレベルになる。このストローブ
信号がＨレベルの時間の間はドライブ回路１０２が駆動
され、発熱素子１０４には、そこに印加されている電圧
Ｖに基づき電流Ｉが流れる。FIG. 1 is a block diagram illustrating the principle of an embodiment of the present invention. In the figure, an FF for strobe signal generation that determines the time for applying energy to the heating element.
101 generates a strobe signal 110 for each print cycle. The FF 101 is set by the cycle signal 109 which is regularly input to the FF 101 every cycle, and the strobe signal 110 becomes H level. The drive circuit 102 is driven while the strobe signal is at the H level, and the current I flows through the heating element 104 based on the voltage V applied thereto.
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１５[Name of item to be corrected] 0015
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１５】発熱素子１０４は図２に示すような負の温
度係数をもっており、本実施例では、２５原子％のアル
ミを含んだクロム合金の薄膜を用いた。この発熱素子１
０４の抵抗値Ｒは、印字開始前に室温で１．６７ｋΩで
あるが、印字の開始とともに発熱素子１０４の温度が上
昇し、その抵抗値は図２のカーブに沿って減少する。The heating element 104 has a negative temperature coefficient as shown in FIG. 2, and in this embodiment, a chromium alloy thin film containing 25 atomic% of aluminum was used. This heating element 1
The resistance R of No. 04 is 1.67 kΩ at room temperature before the start of printing, but the temperature of the heating element 104 increases with the start of printing, and the resistance value decreases along the curve of FIG.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１７[Correction target item name] 0017
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１７】ここで、発熱素子１０４に印加されている
電圧Ｖは固定であり、本実施例の場合には２４Ｖとし
た。そのため、発熱素子１０４に流れる電流ＩはＩ＝２
４／（Ｒ＋ｒ）であるが、式（１）より近似的に Ｉ＝２４／Ｒ （２） の式であらわされ、この電流Ｉにより画一的にＲが決定
される。ただし、ドライブ回路１０２のオン電圧は、２
４Ｖに比べて非常に小さいものとして無視した。Here, the voltage V applied to the heating element 104 is fixed, and is 24 V in the case of the present embodiment. Therefore, the current I flowing through the heating element 104 is I = 2
4 / (R + r), which is approximately expressed by the equation (1) as I = 24 / R (2), and R is uniformly determined by this current I. However, the on-voltage of the drive circuit 102 is 2
Ignored it as being very small compared to 4V.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２０[Correction target item name] 0020
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２０】電流検出器１０５で検出された電流ＩがＩ
０より大きくなる、すなわち発熱素子１０４の温度がＴ
０を越えると、比較器１０７の出力がＨレベルからＬレ
ベルに変化し、ＦＦ１０１をリセットしてストローブ信
号をＬに落とす。そのため、駆動回路１０２の動作が停
止し、発熱素子１０４に電流が流れなくなる。The current I detected by the current detector 105 is I
0, that is, the temperature of the heating element 104 is T
When it exceeds 0, the output of the comparator 107 changes from the H level to the L level, and the FF 101 is reset to drop the strobe signal to L. Therefore, the operation of the drive circuit 102 is stopped, and the current does not flow to the heating element 104.
【手続補正５】[Procedure Amendment 5]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２２[Name of item to be corrected] 0022
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２２】しかし、発熱素子はガラス基材の表面に配
置されているため、ガラス器材に畜熱が生じており、次
なる印字信号が印加される直前の発熱素子の温度は室温
まで低下していない。この様な蓄熱の累積が印字品質を
劣化させる原因であるが、本発明では、次なる印字周期
のストローブ信号Ｓ２がＨレベルになり発熱素子１０４
の温度が上昇した時、前記したＳ１の場合と同様に、目
的温度Ｔ０に到達すると同時に比較器１０７が働き、Ｆ
Ｆ１０１がリセットされストローブ信号がｔ３のタイミ
ングでＬレベルになる。この様に、印字のためのストロ
ーブ信号の時間幅が発熱素子自体の温度で制御されるこ
とから、発熱素子の温度を常に一定に保つことが可能と
なる。However, since the heating element is arranged on the surface of the glass substrate, heat storage occurs in the glass equipment, and the temperature of the heating element immediately before the next print signal is applied is lowered to room temperature. Absent. Such accumulation of heat storage is a cause of deteriorating the print quality, but in the present invention, the strobe signal S2 of the next print cycle becomes H level and the heat generating element 104.
When the temperature rises, the comparator 107 is activated at the same time when the target temperature T0 is reached, as in the case of S1 described above.
F101 is reset and the strobe signal becomes L level at the timing of t3. In this way, since the time width of the strobe signal for printing is controlled by the temperature of the heating element itself, it is possible to always keep the temperature of the heating element constant.
【手続補正６】[Procedure correction 6]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２３[Name of item to be corrected] 0023
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２３】図３は、発熱素子３２素子のサーマルヘッ
ド全体の回路を示す。シリアル入力Ｓｉｎは、クロック
信号Ｃｌｏｃｋとともに図４に示すタイミングでサーマ
ルヘッドに入力され、シフトレジスタ４０１でシリアル
からパラレルに変換され、ラッチ信号Ｌａｔｃｈのタイ
ミングでラッチ４０２に格納される。同時にＦＦ５３６
から５６７がセットされてＡＮＤゲート４０３から４３
４の片入力がＨレベルになり、ラッチ４０２のデータが
Ｈレベルのものだけ出力がＨレベルとなって、それに対
応するドライブ回路４３５から４６６が動作状態とな
り、発熱素子Ｒ１からＲ３２に電流が流れ発熱する。例
えば、ラッチ４０２の奇数番目のみデータがＨレベルの
とき、奇数番の発熱素子にのみ電流が流れる。FIG. 3 shows a circuit of the entire thermal head having 32 heating elements. The serial input Sin is input to the thermal head together with the clock signal Clock at the timing shown in FIG. 4, converted from serial to parallel by the shift register 401, and stored in the latch 402 at the timing of the latch signal Latch. FF536 at the same time
To 567 are set and AND gates 403 to 43
One of the inputs 4 becomes H level, the output of only the data of the latch 402 is at H level, the output becomes H level, the drive circuits 435 to 466 corresponding thereto become in the operating state, and the current flows through the heating elements R1 to R32. Fever. For example, when only the odd-numbered data of the latch 402 is at the H level, the current flows only in the odd-numbered heating elements.
【手続補正７】[Procedure Amendment 7]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２４[Name of item to be corrected] 0024
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００２４】この電流値は、検出用抵抗器４７２から５
０３に生じる電位差によりＡ／Ｄコンバータ４６９で検
出される。比較器４７１は予め設定器４７０で設定され
た電圧値とＡ／Ｄコンバータ４６９の出力電圧とを比較
し、設定電圧を超えるとパルスを出力し、これによりＦ
Ｆ５３６から５６７がリセットされてＡＮＤゲート４０
３から４３４が閉じ、発熱素子Ｒ１からＲ３２に流れる
電流が遮断される。この電流が流れる時間は、発熱素子
Ｒ１からＲ３２の各々の蓄熱状態により変化し、蓄熱が
大きいと短くなる。This current value is detected by the detecting resistors 472 to 5
The potential difference generated at 03 is detected by the A / D converter 469. The comparator 471 compares the voltage value set by the setter 470 with the output voltage of the A / D converter 469, and outputs a pulse when the voltage exceeds the set voltage.
AND gate 40 after resetting F536 to 567
3 to 434 are closed, and the current flowing from the heating elements R1 to R32 is cut off. The time during which this current flows changes depending on the heat storage state of each of the heating elements R1 to R32, and becomes shorter when the heat storage is large.
【手続補正８】[Procedure Amendment 8]
【補正対象書類名】図面[Document name to be corrected] Drawing
【補正対象項目名】図１[Name of item to be corrected] Figure 1
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【図１】 [Figure 1]
───────────────────────────────────────────────────── フロントページの続き (72)発明者 岡本 崇司 小浜市野代４号土淵31−２進工業株式会社 内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Okamoto No. 4 Noshiro, Obama City Dobuchi 31-2 Shinshin Kogyo Co., Ltd.
Claims (2)
成した発熱素子と、前記電気抵抗の変化に基づき前記発
熱素子の温度を検出する回路と、検出された前記温度を
基に前記発熱素子への印加エネルギーを制御する回路と
を具備することを特徴とするサーマルヘッド。1. A heating element formed of a material having a large temperature dependency of electric resistance, a circuit for detecting the temperature of the heating element based on a change in the electric resistance, and the heating element based on the detected temperature. A circuit for controlling energy applied to the thermal head.
て、印加エネルギーを制御する回路は、発熱素子の到達
温度を予め設定し、前記発熱素子の温度が前記到達温度
に到達すると同時にエネルギーの供給を中止し、前記発
熱素子の温度を一定に制御することを特徴とするサーマ
ルヘッド。2. The thermal head according to claim 1, wherein the circuit that controls the applied energy presets the temperature reached by the heating element, and stops supplying energy at the same time when the temperature of the heating element reaches the reached temperature. The thermal head is characterized in that the temperature of the heating element is controlled to be constant.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4071014A JPH07205469A (en) | 1992-03-27 | 1992-03-27 | Thermal head |
| US08/036,831 US5422662A (en) | 1992-03-27 | 1993-03-25 | Thermal printer head having current sensors connected to heating elements |
| EP93105048A EP0562626B1 (en) | 1992-03-27 | 1993-03-26 | Thermal printer head having current sensors connected to heating elements |
| DE69304110T DE69304110T2 (en) | 1992-03-27 | 1993-03-26 | Thermal print head whose heating elements are equipped with current sensors |
| KR1019930004769A KR960016609B1 (en) | 1992-03-27 | 1993-03-26 | Thermal printer-head having current sensor connected to heating elements |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4071014A JPH07205469A (en) | 1992-03-27 | 1992-03-27 | Thermal head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07205469A true JPH07205469A (en) | 1995-08-08 |
Family
ID=13448234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4071014A Pending JPH07205469A (en) | 1992-03-27 | 1992-03-27 | Thermal head |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5422662A (en) |
| EP (1) | EP0562626B1 (en) |
| JP (1) | JPH07205469A (en) |
| KR (1) | KR960016609B1 (en) |
| DE (1) | DE69304110T2 (en) |
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| JPS62116168A (en) * | 1985-11-15 | 1987-05-27 | Hitachi Ltd | Thermal head controlling system |
| DE3741799A1 (en) * | 1987-12-07 | 1989-06-15 | Siemens Ag | THERMAL PRINTING PROCESS |
| US5132709A (en) * | 1991-08-26 | 1992-07-21 | Zebra Technologies Corporation | Apparatus and method for closed-loop, thermal control of printing head |
-
1992
- 1992-03-27 JP JP4071014A patent/JPH07205469A/en active Pending
-
1993
- 1993-03-25 US US08/036,831 patent/US5422662A/en not_active Expired - Lifetime
- 1993-03-26 DE DE69304110T patent/DE69304110T2/en not_active Expired - Fee Related
- 1993-03-26 EP EP93105048A patent/EP0562626B1/en not_active Expired - Lifetime
- 1993-03-26 KR KR1019930004769A patent/KR960016609B1/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100780918B1 (en) * | 2002-07-11 | 2007-11-30 | 사이버 이매징 가부시키가이샤 | Print control device and method of printing using the device |
| JP2013075507A (en) * | 2011-09-13 | 2013-04-25 | Kyocera Corp | Printer |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0562626A1 (en) | 1993-09-29 |
| DE69304110T2 (en) | 1997-01-23 |
| EP0562626B1 (en) | 1996-08-21 |
| KR960016609B1 (en) | 1996-12-16 |
| US5422662A (en) | 1995-06-06 |
| DE69304110D1 (en) | 1996-09-26 |
| KR930019412A (en) | 1993-10-18 |
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Legal Events
| Date | Code | Title | Description |
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| A02 | Decision of refusal |
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